Magnetic properties of nanosized mixed valent manganites CaMnO 3 and Ca 0.7La 0.3Mn 1− xCe xO 3 ( x = 0; 0.2)

Abstract

Nanosized mixed valent perovskite manganites CaMnO 3, La doped Ca 0.7La 0.3MnO 3 (S1) and Ce co-doped Ca 0.7La 0.3Mn 0.8Ce 0.2O 3 (S2) samples were synthesized by the modified glycine-nitrate procedure. Their magnetic properties were investigated by M( T) measurements in both ZFC and FC regimes in several applied DC magnetic fields, as well as by AC susceptibility measurements. Nanosized CaMnO 3 exhibits similar behavior as its bulk counterpart with the antiferromagnetic transition temperature T N = 120 K. Obtained magnetization curves for S1 and S2 display behavior typical for magnetic nanoparticle systems, such as irreversibility of ZFC and FC curves, and field dependence of the magnetization maximum in ZFC branches. Field dependence of the magnetization maxima ( T max versus H 2/3) as well as AC susceptibility behavior (frequency dependence of T max) point to the presence of considerable interparticle interactions. Consequently, below T max the formation of super spin-glass state can be assumed.